Abstract
SummaryThe effects of 96 combinations of N, K and Mg were studied in three crops of lettuce grown in peat; there were two sources of N, Nitrochalk (26% N) and sulphur-coated urea (32% N), and molybdenum was included as an extra factor in one crop. The yield and proportion of hearted lettuce increased with applied N until the peat contained 60 mg N I-1. In two crops higher N concentrations were unfavourable, due to increased acidity in the peat which resulted in greater uptake of Mn by the plants. The yield and the proportions of both hearted and of marketable lettuce declined as the Mn content of the leaves increased. In the third crop, which was not affected by Mn toxicity, there was little response to N over the range 60–250 mg N I-1. The yield and quality of the produce improved with increasing K until the peat contained 200 mg K I-1, but concentrations of up to 600 mg K I-1 had little further effect. The N and K contents of the leaves corresponding to maximum yield were 5% N and 8% K. There was no response to added Mg. The yield and proportion of hearted lettuce were increased by the addition of Mo in plots receiving the heaviest dressing of Nitrochalk. The increase in the proportion of hearted lettuce was greatest in plots also receiving sulphur-coated urea. The water-soluble phosphate content of the peat increased from 19 mg P I-1 to >50 mg P I-1 as the pH of the peat declined from 6–7 to 5.5 in response to increasing N application rates.
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Claims 11
Claim · model-written summary
Applied nitrogen increased lettuce yield and hearting until peat reached 60 mg N I-1.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- applied Ne0
- Outcome
- yield and proportion of hearted lettucee0
- Direction
- increasede0
- Value
- 60 mg N I-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The yield and proportion of hearted lettuce increased with applied N until the peat contained 60 mg N I-1.”
Claim · model-written summary
Higher nitrogen concentrations were unfavorable in two crops because peat acidity increased manganese uptake.
- Treatment
- higher N concentrationse0
- Outcome
- uptake of Mn by the plantse0
- Qualifier
- due to increased acidity in the peate0
Not reportedTaxon
Verbatim
e0“In two crops higher N concentrations were unfavourable, due to increased acidity in the peat which resulted in greater uptake of Mn by the plants.”
Claim · model-written summary
Lettuce yield and hearting and marketability declined as leaf manganese increased.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Outcome
- yield and the proportions of both hearted and of marketable lettucee0
- Direction
- declinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The yield and the proportions of both hearted and of marketable lettuce declined as the Mn content of the leaves increased.”
Claim · model-written summary
The third crop had little nitrogen response between 60 and 250 mg N I-1.
Not reportedTaxonComparator
Verbatim
e0“In the third crop, which was not affected by Mn toxicity, there was little response to N over the range 60–250 mg N I-1.”
Claim · model-written summary
Potassium improved yield and quality up to 200 mg K I-1 in peat.
- Treatment
- increasing Ke0
- Outcome
- yield and quality of the producee0
- Direction
- improvede0
- Value
- 200 mg K I-1e0
Not reportedTaxonComparator
Verbatim
e0“The yield and quality of the produce improved with increasing K until the peat contained 200 mg K I-1, but concentrations of up to 600 mg K I-1 had little further effect.”
Claim · model-written summary
Potassium up to 600 mg K I-1 had little further yield or quality effect.
- Treatment
- Ke0
- Outcome
- yield and quality of the producee0
- Direction
- little further effecte0
- Value
- 600 mg K I-1e0
Not reportedTaxonComparator
Verbatim
e0“The yield and quality of the produce improved with increasing K until the peat contained 200 mg K I-1, but concentrations of up to 600 mg K I-1 had little further effect.”
Claim · model-written summary
Leaf nitrogen and potassium at maximum yield were 5% and 8%, respectively.
Not reportedTaxon
Verbatim
e0“The N and K contents of the leaves corresponding to maximum yield were 5% N and 8% K.”
Claim · model-written summary
Added magnesium produced no lettuce response.
Not reportedTaxonComparator
Verbatim
e0“There was no response to added Mg.”
Claim · model-written summary
Molybdenum increased lettuce yield and hearting under the heaviest Nitrochalk dressing.
- Taxon
- lettuceLactuca sativae0
- Treatment
- addition of Moe0
- Outcome
- yield and proportion of hearted lettucee0
- Direction
- increasede0
- Qualifier
- heaviest dressing of Nitrochalke0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The yield and proportion of hearted lettuce were increased by the addition of Mo in plots receiving the heaviest dressing of Nitrochalk.”
Claim · model-written summary
The greatest increase in hearted lettuce occurred with both molybdenum and sulphur-coated urea.
- Taxon
- lettuceLactuca sativae0
- Treatment
- sulphur-coated ureae0
- Outcome
- proportion of hearted lettucee0
- Direction
- greateste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in the proportion of hearted lettuce was greatest in plots also receiving sulphur-coated urea.”
Claim · model-written summary
Water-soluble peat phosphate rose from 19 to over 50 mg P I-1 as peat pH declined with nitrogen application.
- Treatment
- increasing N application ratese0
- Outcome
- water-soluble phosphate content of the peate0
- Direction
- increasede0
- Value
- >50 mg P I-1e0
- Qualifier
- 19 mg P I-1e0
Not reportedTaxon
Verbatim
e0“The water-soluble phosphate content of the peat increased from 19 mg P I-1 to >50 mg P I-1 as the pH of the peat declined from 6–7 to 5.5 in response to increasing N application rates.”
The same questions in other papers
molybdenum atom · yield · Lactuca sativa (garden lettuce)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 papers →nitrogen · yield · Lactuca sativa (garden lettuce)Positive and negative results
60 papers in the same direction as this paper · 17 in the opposite direction · 1 reporting no difference from an alternative
- no effect
- negative
- no effect
75 papers more in this group
See all 79 papers →potassium · quality: general · Lactuca sativa (garden lettuce)Results agree
1 paper in the same direction as this paper
- no effect
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.